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PostPosted: Wed Mar 13, 2019 10:47 am 
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Or wait, this cart doesn't even connect the 2A03 audio, right? Then there's nothing to measure...

Lagrange point tends to put its loud channels at 10-12. The Family Noraebang is always at 13-15. I guess equivalent headroom would be -9db?

The Lagrange point default mixe is 1100, so -9dB would be 100.

Edit: having an arithmetic fail. 11-9=2.


Last edited by rainwarrior on Fri Mar 15, 2019 11:05 am, edited 1 time in total.

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PostPosted: Wed Mar 13, 2019 1:57 pm 
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When krzysiobal took a look at the K-663A he said that it was a bit noisier than a YM2413 anyway.


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PostPosted: Wed Mar 13, 2019 2:32 pm 
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Alright, I figured out where the rhythm mode output had been disconnected and hooked it up, so that should be working in 2.4 beta 16.

B00daW wrote:
When krzysiobal took a look at the K-663A he said that it was a bit noisier than a YM2413 anyway.

Well, this is a practical headroom issue rather than an accurate mix issue. Because of NSF's fortunate/unfortunate multi-chip accident, everything has to be relative to the 2A03's range, and there's only so much that's practical in 16 bits here. The relative mix for each cart is important, but this cart has nothing else to be relative to, so we can set an arbitrary volume for it. I think the most practical thing is just give it a 'mixe' at -9db and let that put it in line with expected range for VRC7 usage. I.e. if the player already has headroom for Lagrange Point, it will automatically accommodate this as well at that relative volume.


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PostPosted: Wed Mar 13, 2019 11:51 pm 
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Wonderful.-9 dB is 0x7C 0xFC in the mixe chunk, right?


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PostPosted: Wed Mar 13, 2019 11:55 pm 
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It's a signed 16-bit integer in units of 1/100 db, and the reference level for VRC7 is 1100, so the value should be 1100 - 900 = 100. ($64, $00)

Edit: having an arithmetic fail. 11-9=2.


Last edited by rainwarrior on Fri Mar 15, 2019 11:05 am, edited 1 time in total.

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PostPosted: Thu Mar 14, 2019 11:09 pm 
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I still don't get it. If the default volume of the VRC7 is +11 dB, meaning 11 dB louder than the APU square wave, or 1100 dec, and we want 9 dB less than that, why is it 100 and not 200? 1100-900 is 200, not 100, after all.


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PostPosted: Thu Mar 14, 2019 11:13 pm 
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Yes that's correct, I made a mistake in my arithmetic. Twice. Ha.

1100 - 900 = 200.

Though really an extra dB or two wouldn't hurt here. The VRC7 is the loudest relative expansion, aiming a little lower is probably closer to the average loudness of things. Even 0 could be a good value to use here.


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PostPosted: Fri Mar 15, 2019 11:30 am 
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Given the current schema, is VRC7+K-663A multichip NSF a thing since y'all are lumping them together?


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PostPosted: Fri Mar 15, 2019 11:51 am 
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No you don't get two. The 'VRC7' chunk replaces the VRC7 with a variant (same as that TNS cart with a YM2413 would do).

Is K-663A a meaningful variant of YM2413 or is this just somebody else's name for an identical part?


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PostPosted: Fri Mar 15, 2019 11:55 am 
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As far as we can tell, it's just a Korean clone of a real YM2413.


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